Add update notifications for new Pollora versions

[lhall-amphibee]

Feature Request

Add notifications in WordPress admin when a new version of Pollora is available.

Proposed Features

1. Dismissable admin notice

   • Show a banner in WP admin when an update is available
   • Display current version and new version
   • User can dismiss the notice

2. Site Health integration

   • Add an entry in Tools > Site Health
   • Show if Pollora is up to date or needs an update
   • Display current and latest version

Benefits

• Users stay informed about available updates
• Encourages keeping Pollora up to date
• Uses WordPress's native notification systems